#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<sys/types.h>
#include<sys/wait.h>
#include<unistd.h>

void writer(int wfd)
{
    const char *str = "hello father, I am child";
    char buffer[128];
    int cnt = 0;
    pid_t pid = getpid();
    while(1)
    {
        snprintf(buffer, sizeof(buffer), "message: %s, pid: %d, count: %d\n", str, pid, cnt);
        write(wfd, buffer, strlen(buffer));
        cnt++;
        sleep(1);
    }
}
void reader(int rfd)
{
    char buffer[1024];
    while(1)
    {
        ssize_t n = read(rfd, buffer, sizeof(buffer)-1);
        (void)n;
        printf("father get a message: %s", buffer);
    }
}


int main()
{
    //1. 创建匿名管道
    int pipefd[2];
    int n = pipe(pipefd);
    if(n < 0)   return 1;

    //2. 创建父子进程，if分流，进行通信
    pid_t id = fork();
    if(id == 0)
    {
        //child     负责写
        close(pipefd[0]);
        writer(pipefd[1]);
        exit(0);
    }
    //father    负责读
    close(pipefd[1]);
    reader(pipefd[0]);
    wait(NULL);     
    return 0;
}
